STN displays having high contrast, with purple polarizer and residual birefringence causing greenish-gold or purplish-blue coloring
US5550660A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 22, 1993 |
| Grant date | Aug 27, 1996 |
| Priority date | — |
| Expiry date | Nov 22, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133533
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A display system (10) or display (12) has a supertwisted nematic liquid crystal cell (30) located between first and second polarizing filters (24, 54) that have respective first (26) and second (56) transmission axes that form respective polar angles (A, D) with a reference plane (28). The first polarizing filter passes a neutral polarized color along the first transmission axis and has another transmission axis (27) orthogonal to the first transmission axis and transmissive of a purple polarized color; the second polarizing filter is of a neutral density type. The cell has first and second electrode structures (32, 34) confining a liquid crystal composition, each having an inner surface with respective liquid crystal alignment directions (38, 40) of inner-surface-contacting directors of the liquid crystal composition forming respective polar angles (B, C) with the reference plane. The second polarizing filter may be associated with a translucent film (64) to reflect light toward the second polarizing filter. Preferred polar angles include: A=110.degree.; B=150.degree.; C=30.degree.; and D=-10.degree.. With those angles, the display has excellent contrast, viewability, and color hu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.